Malaria is a life-threatening disease of the blood, caused by parasites and transmitted to humans through the bite of the Anopheles mosquito. Malaria in humans is caused by four species of the protozoan Plasmodium: P. falciparum, P. vivax, P. malariae and P. ovale. When an infected mosquito bites a human, the parasite enters the host’s liver and lays dormant for about 5-16 days, reproducing asexually. It is after this time when the symptoms of malaria are first seen.
Malaria can only be transmitted via the Anopheles mosquito and in order to transmit this disease they must be carrying an infected sample of blood from the previous host, which is then injected into the new host through their bite.
The host’s response to the injection of the protozoan Plasmodium is to develop antibodies when it is in the red blood cells. However, as the surface antigen of the cell membrane of the disease changes over time, the antigens in the body are sometimes unable to recognise new forms of the protozoan, meaning the host will be infected. Also, as the Plasmodium isolates itself in the liver for 5-16 days, it is unable to be treated by the host’s immune system.
The major symptoms of malaria are a fever that could exceed 40oC, shivering fits, headache, nausea and profuse sweating, and depending on the species of plasmodium can occur every 48 hours (for P. falciparum, P. vivax and P. ovale) or ever 72 hours (P. malariae). Another symptom of malaria is that it could re-enter the liver and infect the host again. After the malarial attack occurs, the host body will return to regular body temperature, however they will feel weak and often suffer from anaemia (blood loss) as a result of the red blood cells and haemoglobin lost during the malarial attack. The most serious and dangerous form of malaria is caused by the P. falciparum Plasmodium which will cause the host to feel weak and if left untreated, the host will eventually die. Typically, the symptoms of malaria will last for about 6-10 hours, occurring in cycles.
Some treatment methods for malaria are antimalarial drugs, such as chloroquine or quinine, which aims to reduce temperature or cure the infection. Also, Artemisinin-based combination therapy (ACT) is a method of treatment for malaria which is recommended by the World Health Organisation (WHO). ACT is artemisinin combined with a partner drug, where the role of the artemisinin is to reduce the amount of Plasmodium parasites in the body within the first 3 days while the partner drugs eliminate all other parasites in the host.
In order to prevent and control malaria, individuals should wear protective clothing, use insect repellent and have mosquito nets over beds in malaria infected areas. For people who are visiting malaria infected areas, drugs such as chloroquine should be taken to prevent and cure malaria. To prevent the spread of malaria in areas of the world that aren’t infected, individuals cannot donate blood after recently visiting malarial areas. The spread of malaria can also be prevented by destroying adult mosquitoes by spraying insecticides, draining swamps and spraying vehicles that have arrived from malarial areas to malaria-free areas in the world.
Antibiotics are chemicals that are capable of destroying or inhibiting the growth of the bacteria that causes diseases, without destroying the host. Antibiotics have a variety of ways in which they can destroy the bacteria:
– Some accumulate in the bacteria cell and prevent them from creating a new cell wall through cell division
– Some destroy the cell membrane, which in turn destroys the bacteria
– Some interfere with the process of protein synthesis so the bacteria is unable to make essential compounds, this result in cell death of the bacteria
There are two different forms of antibiotics, being narrow-spectrum and broad-spectrum. Narrow-spectrum antibiotics are used for only specific families of bacteria, whereas broad-spectrum antibiotics are used for a wide range of bacteria, such as Penicillin.
Antibiotic resistance is when the bacteria that causes disease develops resistant strains that do not respond to antibiotics, allowing them to continue to multiply and cause harm. This problem has greatly developed more recent times with BBC News posting an article on 19th November 2015, discussing that there has been a bacteria found that is completely resistant to antibiotics. After bacteria was identified to be resistant to a “last-resort” drug, known as Colistin, in patients and livestock in China, scientists have stated that this resistance could spread and develop around the world, increasing the risk and severity of diseases to humans and other organisms.
Antibiotic resistant has a wide variety of causes such as:
– The over-prescription and overuse of antibiotics when treating diseases that not caused by bacteria, such as viruses. So, as antibiotics do not treat viruses, the bacteria is given more time to reproduce and build more resistant strains
– Another cause is the incompletion of the entire antibiotics course, with patients deciding to no longer take antibiotics when they feel the symptoms have disappeared. This is an issue as, although the symptoms may no longer be felt, the bacteria may not necessarily be killed, allowing it to grow and continue to develop resistant strains
– Antibiotic resistance is further accelerated through the use of antibiotics on livestock used for human food, such as chickens and cows. Antibiotics are used on these organisms to prevent them from infections and also helps with their growth, however, it is currently a cause in developing antibiotics with resistant strains
– Poor hygiene and sanitation is yet another cause to developing antibiotic resistant strains as those who do not clean and wash themselves with adequate chemicals, such as soap, sufficiently, are leaving bacteria and microorganisms within the individual to develop and become more resistant to antibiotics. These bacteria can then spread to larger organs in the body and cause detrimental harm to the individual
Some strategies that could be implemented to assist reduce the development of antibiotic resistance are:
– Antibiotics should only be prescribed to the patient when needed and should be specifically related to the bacterial disease that is to be treated
– Antibiotics being prescribed to the patient should be narrow-spectrum, rather than broad-spectrum, targeting the pathogen that is infecting the host
– Antibiotics that are prescribed to the individual should only be ingested by that individual and no one else
– Antibiotics should never be prescribed or ingested for viruses or any other disease that is not caused by bacteria
– Hygiene rules should be strictly followed in public places, such as hospitals, where the is a high prevalence of disease
The ‘No Jab, No Pay’ policy is a program that allows families to receive certain rebates and benefits by removing their rights to object to vaccinations for their children under the age of 20 years. However, if the child is naturally immune to the illness, the family is allowed to apply for an exemption from the vaccination, without losing access to specific rebates and benefits associated with the policy.
Since its introduction at the beginning of 2016, the ‘No Jab, No Pay’ policy has been extremely effective in the prevention of diseases, having over 148,000 children vaccinated within the first 6 months of its introduction. The percentage of children between 1-5 years old has increased from 90% to now over 93% due to the implementation of this policy. Therefore, the ‘No Jab, No Pay’ policy has been extremely effective since it implementation in the reduction and prevention of diseases and illnesses throughout Australia’s population.
Smallpox is a disease that is caused by a virus that was once very lethal and caused many deaths worldwide between 1519 and 1979. However, in 1796, an English scientist by the name of Edward Jenner developed a vaccine for this disease but it was not widely accepted, therefore proving ineffective at first. During the 1840s, this vaccine was made free to the people of Britain, however it was still not widely used until the implementation of compulsory vaccinations of this specific disease.
In the 1960s, there were still 33 countries with the smallpox virus present, due to the overcrowding, poor hygiene levels, extreme poverty and poor nutrition in this countries which were all factors contributing to the spread of this disease.
In order to reduce, and eventually diminish, the cases of smallpox throughout the world, the World Health Organisation (WHO) developed a worldwide immunisation program wherein they implemented routine mass immunisations supplementation given on special immunisation days (among other measures).
This program proved to be extremely effective, ultimately leading to the WHO declaring that, in 1979, they had completely removed and diminished all cases of smallpox worldwide.
Diphtheria is caused by highly contagious and fast acting bacteria that is often transmitted via close contact with respiratory droplets and will often kill the host within a week of noticing symptoms.
Prior to the development of a vaccine for diphtheria, mortality rates or this disease were extremely high, with over 800 deaths in 1920 in Australia alone.
The first vaccine for diphtheria was released in 1923 but was not highly effective instantly, taking 20-30 years until the cases were reduced from regular and large scale outbreaks, to just occasional outbreaks. Also, it was not until the 1940s where the first vaccinations for diphtheria were introduced into Australia, which saw a rapid decrease in the cases of diphtheria, not just throughout Australia, but worldwide.
The introduction of the World Health Organisation’s Expanded Program on Immunisation (WHO EPI) ensured children worldwide were being correctly vaccinated against diphtheria and other deadly diseases and viruses. This program saw the percentage of children vaccinated against diphtheria raise to 80% in 1990, which in turn decreased the total mortality rates of diphtheria worldwide.
Since the implementation of this program, there was only one single case of reported diphtheria in Australia between 1994-2006, showing the positive effects this program is having in reducing the incidence of diphtheria worldwide. However, diphtheria has not yet been completely eradicated and due to people refusing or neglecting to be vaccinated against this disease, there is still a possibility of an outbreak of diphtheria.
Poliomyelitis (or more commonly known as polio) is a disease transmitted through the inhalation of infected droplets or by direct contact with the disease itself. Polio is quite severe, with 50% of cases resulting in death, nerve damage or paralysis.
After the first major outbreak, thousands of years ago, a vaccine was being developed and it was not until 1955 where Jonas Salk developed the first vaccine. In the following years, of those who had the vaccine, 200 people contracted polio with only 11 deaths in total.
Due to this vaccine not being completely safe and reliable, another scientist, by the name of Albert Sabin, developed a renewed vaccine which resulted in a 60-70% decrease in the disease. Furthermore, the introduction of the EPI by the WHO in 1974 further reduced the cases of polio and in 1988, the World Health Assembly (WHA) introduced the Global Polio Eradication Initiative which involved the widespread use of vaccinations for children under the age of 5 years in countries infected with polio.
This program proved to be extremely effective in the immunisation of polio, reducing the cases of polio by 99% by the year 2000. Also, Australia has had no cases of polio since the introduction of this initiative in 1988, further demonstrating its positive effects on the reduction and prevention of polio cases throughout Australia and worldwide.
Diabetes is one of the biggest epidemics of the 21st century in Australia and the entire world. Diabetes is a non-infectious disease caused by the bodies inability to produce insulin or use it effectively. Diabetes results in high blood glucose levels in the blood and abnormal metabolism of carbohydrates.
Diabetes is extremely prevalent in today’s society with over 280 people in Australia being diagnosed with both types (Type 1 and Type 2) of diabetes every day and around 1.7 million Australians with diabetes in total. While diabetes affects the individual quite greatly, it also affects those around them as most people diagnosed with diabetes have a family member or carer who supports them with their disease. This results in over 2.4 million Australians being affected by diabetes every day, whether they are diagnosed with the disease themselves, or have a friend or family member with the disease. With over 100,000 Australians being diagnosed with diabetes during 2015, it is clear that this disease is still prevalent and is growing to become one of the world’s biggest non-infectious diseases.
Both Type 1 and Type 2 diabetes have some symptoms that apply to both types such as:
– More regular hunger and fatigue due to the bodies inability to produce enough insulin or use it effectively, leading to lower levels of glucose in cells
– Blurred vision due to the changing of fluids in your body
– Dry mouth and itchy skin as your body is using liquids to produce more urine, resulting in dehydration
– Urinating more regularly and being thirsty more often high levels of glucose in the blood
However, there are some symptoms that only apply to Type 1 diabetes, such as unplanned weight loss and nausea and vomiting, and some that apply to Type 2 only, for example, pain or numbness in lower limbs and sores and cuts taking longer to heal.
While Type 1 diabetes is most commonly caused by the body’s immune system attacking the insulin-producing cells in the pancreas, eventually killing them, Type 2 diabetes can be caused by multiple different factors such as:
– Being overweight or having a lack of physical activity in daily life as this can cause insulin resistance and lead to diabetes
– Insulin resistance, which is a condition in which, muscles, the liver and fat cells do not efficiently use insulin
– Genes and family history
Both Type 1 and Type 2 diabetes are managed and treated in very similar ways with some procedures being used to treat and manage both types of the disease, there are some procedures that must be used for a specific type of diabetes. The general management of diabetes includes regular monitoring of blood glucose levels, taking part in regular exercise and sustaining a healthy, balanced diet. However, Type 1 diabetes also requires the individual to replace insulin levels through lifelong insulin injections or through the use of an insulin pump.
One plant disease that is being prevented from entering into Australia is the disease called citrus greening disease, which is caused by bacterium carried by an insect known as psyllid.
There are many measures being taken to help prevent the entry of this disease into Australia such as the inspection of all plant matter brought in from countries known to have traces of the disease, with materials suspected with having the disease being confiscated and managed correctly. Also, if any plants are not destroyed, they are kept in a quarantine area to assist in the prevention of this disease entering Australia.
These strategies help prevent the entry of citrus greening disease into Australia as they reduce the risk of pathogens containing the disease from entering, and any pests or plants that are suspected to be carrying the disease become known in quarantine areas before contact with other plants in Australia.
So far, this program has been highly effective in the prevention of citrus greening disease as there has never been a case of this disease reported in Australia.
A disease that is being prevented from entering Australia, via animals, is enzootic bovine leucosis (EBL) which is present in cattle all over the world and is caused by a lymphoid tumour which effects all body systems of the cattle.
While this disease has been eradicated from Australia’s dairy herds since 2012, there are still measures being taken in order to prevent the disease from re-entering Australia’s cattle. One measure is the implementation of a program, in Queensland, which aims to continue dairy freedom by separating dairy herds from untested beef cattle, and another measure is the constant testing of milk to detect any trace of the EBL disease and stop it from spreading into Australia.
These strategies have proven to be effective in the prevention of the EBL disease and its entry into Australia as there has been no reported cases of the disease since the program was introduced in 2012.
A disease that is currently present in Australian plants that is being treated to prevent it from spreading across Australia is Myrtle rust. Myrtle rust is a fungus that causes disease in plants of the Myrtaceae family.
After its first detection in 2010, the Australian Government worked to try and suppress the outbreak and eradicate the disease through a number of strategies. Some of these strategies included the removal of host material at infected properties, application of fungicide to continue the suppression of the disease and the use of spore trapping to establish whether the rust was spreading.
However, these strategies proved unsuccessful in the eradication of Myrtle rust as the disease continued to spread across Australia to other species of flora. This led the Government to come up with the decision to design a new program which managed the disease rather than eradicate it as it was declared unfeasible to completely eradicate the disease from Australia.
Equine influenza is a viral and highly contagious disease in animals, mainly horses. Some measures that were taken to prevent the spread of this disease across Australia were to quickly import vaccines for horses that were required to travel, such as racing horses, all equipment that was suspected to have traces of the disease must be decontaminated, wherever possible, the virus must be killed and public awareness of the disease ensured the public followed procedures that aimed to decrease the risk of pathogens containing the disease.
These measures proved to be extremely effective in preventing the spread of equine influenza across Australian horses and by March 2008, it was declared that all traces of the disease had been eradicated from Australia.
There has recently been a shift in emphasis from treatment and control of diseases to management and prevention as scientists and medical professionals have determined that it is more beneficial to target and eradicate a disease before any serious harm is caused.
Previous treatment and control of plant diseases, such as the potato leafroll virus carried by aphids, would involve the use of insecticide sprays to kill the aphids and control the spread of the disease. However, this strategy had detrimental effects on the environment, was fairly expensive and after some time, the disease developed a resistance to the insecticides, allowing them to grow and develop and spread to other plants.
Due to the detrimental effects of these previously used strategies in treating and controlling the potato leafroll virus, new strategies have been developed which aim to manage and prevent this disease instead. Some strategies used to manage the potato leafroll virus are to use certified seed tubers and to chemically control the disease by applying insecticides from early to mid-season if aphids and the potato leafroll virus are present. These strategies aim to reduce the spread, and assist in the management and prevention of this disease in Australia.
The cattle tick is a parasite of cattle that can significantly reduce the weight of cattle and prevent weight gain and milk production. If left untreated, cattle tick can lead to mass spread between cattle, ultimately killing off masses of cattle.
Cattle tick has been treated and controlled through the breeding of tick-resistant cattle, chemical treatment and pasture spelling. However, as the risk of this parasite spreading is not completely eradicated, there must be other actions and measures taken in order to manage and prevent this parasite from infecting other herds of cattle.
Some measures taken to assist in the prevention and management of cattle tick are that states such as Queensland have separated their cattle herds into herds that have the tick and herds that do not. Those herds without the tick are bred and continue living as normal, however, those that do have the tick are placed in infested zones and are then quarantined to reduce the risk of the tick spreading between herds and infecting other cattle.